Mail migration
Compare published exchanges with the new provider’s requirements after a DNS update. Cached responses can take time to expire.
Free email tool
MX record checker
Inspect a domain’s mail-routing records and identify its receiving provider.
Put the result to work
Read the mail route, not just a green result
MX records name the servers a domain publishes for incoming mail. This lookup helps diagnose a domain setup, compare priorities and distinguish an explicit refusal of mail from an inconclusive DNS lookup.
Enter the domain
Use the part after @, for example example.com. Do not enter a full website path.
Inspect each server
Read the exchange hostname and preference number. A smaller number has a higher preference.
Check the wider setup
If the lookup is empty or fails, review DNS and retry before declaring a mailbox invalid.
Worked examples
What the evidence tells you
Illustrative scenarios, not live results for the addresses or records shown. Open a scenario to see the next action.
0110 mx1.example.com / 20 mx2.example.com
Two published routes
A sender normally tries the lower preference number first. These are illustrative hostnames, not live lookup results.
Next action Check that both entries match the mail provider’s setup.
020 .
Explicit null MX
The dot is a deliberate declaration that the domain accepts no email. It is not a server hostname.
Next action Ask for another receiving address.
03No MX records returned
No explicit route found
Missing MX is different from null MX; SMTP can use address-record fallback in some setups.
Next action Check the domain’s A/AAAA records and provider instructions.
Use it with a purpose
Where this tool fits
Delivery troubleshooting
Separate a routing problem from a misspelled local part. An MX lookup cannot tell whether alex@ exists.
Before you decide
Questions about this tool
Does MX prove the mailbox exists?
No. The records apply to the domain, not an individual inbox.
Is a higher number a better server?
No. The number is a preference, not a quality score. Lower numbers are preferred.
Why does my result differ from another resolver?
Cached answers can persist until their TTL expires. A lookup error can also be temporary.
Explore the email provider market share tracker for aggregate MX observations. Technical reference: Null MX specification.
